Liquid diffuser devices are known to be particularly used in agriculture for conveying a unidirectional water flow into a nozzle and direct it to a plate which distributes it in a plurality of directions.
A diffuser device head as described above is known from international application WO2004/050258, on which the preamble of claim 1 is based.
As shown in FIG. 1, this prior art device has a partly hollow central body C, which may be connected to a liquid feed line by means of a connecting sleeve M. Liquid, whose flow direction is substantially coincident with the axis X′ of the device, passes through the sleeve M and is conveyed into a convergent nozzle U, interposed between the central body C and the sleeve M. Liquid is first accelerated in the nozzle U and then directed to a deflector member, downstream of the nozzle U, which member is composed of the plates D and D′, and is adapted to divert flow to a substantially transverse direction, to disperse it outward.
The nozzle U, which may have different diameters according to desired flow rates, and has to be periodically replaced as needed, is coupled to the sleeve M by snap connection means S, which are designed to hold the nozzle U in an axially locked position with respect to the sleeve M, upon mounting the latter on the central body C or dismounting it therefrom.
In practice, this prior art device has certain recognized drawbacks.
When operating in contaminated environments, with high content of dust and earth, the recess of the snap means S fills up with foreign matter, and is no longer able to effectively hold the nozzle U in position. As a result, undue efforts are required for removing and remounting the various parts, which makes nozzle replacement difficult.
Deterioration of the nozzle and sleeve connection also causes accidental disengagement of the nozzle. As the sleeve is screwed onto the central body, gravity force tends to cause removal of a badly connected nozzle, which is irremediably lost in the environment.